When you see a squirrel running around burying nuts in the ground,
that's the way they save up food for the coming fall and winter.
They are called scatter-hoarders, because they scatter their food and hoard it.

Sometimes the squirrels forget where they bury the nuts, and the buried nuts grow and turn into trees.
If a squirrel thinks it is being watched by someone who is going to steal their nuts,
some smart squirrels will even just pretend to dig a hole and bury the nut,
and then move on to another place!